In the medical field, radiographic image capturing apparatuses have been widely used for detecting a radiation applied to a subject from a radiation source and passed through the subject to acquire a radiographic image of the subject. For example, the radiographic image capturing apparatus has an indirect conversion radiation detector containing a scintillator for converting the radiation transmitted through the subject into a visible light and a radiation conversion panel for converting the visible light into electric signals.
In a recently proposed radiation detector, the scintillator is formed by vapor-depositing columnar crystals of CsI or the like on a support board, the columnar crystals are approximately perpendicular to the support board, and the distal end portions of the columnar crystals are located on the radiation conversion panel with a protective layer interposed therebetween (see Japanese Laid-Open Patent Publication No. 2009-068888).
In a case where the radiation is converted into the visible light by the columnar crystals, the visible light passes through column portions of the columnar crystals, is transmitted from the distal end portions of the columnar crystals through the protective layer, and reaches the radiation conversion panel. Then, the incident visible light can be converted to the electric signal in the radiation conversion panel.